The present invention relates to a method of manufacturing an artificially figured veneer or an artificially figured board, and in detail, to a method of efficiently manufacturing an artificially figured veneer or an artificially figured board with a design similar to the figure observed in a natural wood.
Besides, the present invention relates to an artificially figured veneer or an artificially figured board manufactured according to said method.
In general, an artificially figured veneer is manufactured by laminating multiple sheets of material veneers as row material with adhesives and hot pressing them, and then cutting the laminate again so as to obtain a collected veneer with desired thickness.
Up to the present, according to this method of manufacturing, an attempt has been made to prepare an artificially figured veneer with an inexpensive veneer as a material veneer made to appear fancy wood veneer having high market value. For example, an artificially figured veneer with grain of Japanese cedar is made from veneers of Agathis as the row material.
In this case, in order to make an artificially figured veneer so well as to confuse with a natural fancy wood veneer, it is required to faithfully express textures, vessels, grains, etc, which a fancy wood veneer ordinary may have.
Therefore, various methods such as bleaching and coloring of material veneers, specific process of applying an adhesive (to form non-uniform films), insertion of colored papers (resin impregnated papers) between veneers, etc. have been proposed up to present. These proposals are disclosed in, for example, Japanese Patent Laid-Open No. Sho 57-156203, Japanese Patent Laid-Open No. Sho 59-220305 and Japanese Patent Laid-Open No. Sho 57-150503, etc.
However, the artificially figured veneers prepared by these techniques lacked natural feeling, and it could not say that those faithfulness and reproducibility about grains, textures, etc of natural woods were not sufficiently (completely) met.
Further, the artificially figured veneers which are made from material veneers optionally collected various veneers of different kinds of wood with different grains and colors are on the market. Typical example is shown schematically on FIG. 21. Each part of veneer 15 (the parts between the curve of a grain and adjacent curve) was made up of various kinds of wood materials with different textures, and no consideration is given how faithfully specific grain, texture, etc. of a natural wood have been expressed in this type of an artificially figured veneer. As a result, this type of artificially figured veneers bear no resemblance to veneers of natural fancy wood.
By the way, unique pattern so called xe2x80x9cfigurexe2x80x9d is sometime formed in the grain of natural woods. Principal figures known among artisans are such as quilted figure, bird""s-eye figure, peony (BOTAN) figure, quail (UZURA) figure, grape (BUDO) figure, NYORIN figure, bamboo grass (SASA) figure, etc.
The veneers with quilted figure, bird""s-eye figure, etc. are recognized as those having higher value in design and artistic handicraft, and have significantly higher market value than the veneers of same kind of wood without any figure.
FIG. 22 is schematic drawing illustrating a typical example of an artificially figured veneer made resemble to quilted figures observed in a natural wood. For an artificially figured veneer shown in said figure, simply collecting many parts of veneers 15 made from wood materials of different textures is made to resemble the grain curve of a quilted figure, and the grain of such artificially figured veneer is not similar to the grain of a natural fancy wood, and further a design of a quilted figure of natural fancy wood is not expressed faithfully.
As described above, it was difficult to faithfully express the grains of especially high value in design and artistic handicraft, e.g. quilted figure, bird""s-eye figure, etc. observed in natural woods.
As for the method of manufacturing an artificially figured veneer faithfully expressing a figure in the form observed in natural woods in addition to normal grains of a natural wood from natural wood without figures, the method disclosed in Japanese Patent Laid-Open No. Hei 9-123110 may be mentioned.
According to said method, it is possible to express a grain on an artificially figured veneer of artificially figured board with very similar form of a figure observable in natural woods, by
1) preparing a set of multiple sheets of material veneers by rotary cutting a log or repeatedly cutting a wood flitch, wherein said multiple sheets of material veneers are of the same kind of wood and their grains are sequential,
2) embossing concave-convex patterns on every material veneers with press dies respectively having concave-convex patterns corresponding to a site of figure observed in a natural wood on both upper and lower faces of die,
3) laminating the set of thus embossed multiple sheets of material veneers such that their grains again become sequential with adhesive layer interposed between each material veneers, and pressing the laminate between the upper and the lower press dies, and
4) cutting the laminate obtained in the direction crossing the plane of the lamination to manufacture an artificially figured veneer or an artificially figured board with desired thickness.
However, it is required to emboss the material veneer one by one when the material veneer are embossed to form concave-convex pattern, thus said method has the problem in low productivity.
In order to improve productivity, it is useful to emboss multiple sheets of material veneers simultaneously. But simple simultaneous embossing of multiple sheets of material veneers can not achieve uniform embossing of all materiel veneers, and as a result, the problem may occur in which voids may be observed between the set of material veneers embossed simultaneously and the adjacent set of material veneers when laminated after embossing. Said voids not only become harmful on faithful expression of a grain and a figure but also cause failure in adhesion of material veneers, and significantly decrease the strength of an artificially figured veneer.
The present invention is achieved in consideration for the prior art, and its subject is to provide a method of manufacturing an artificially figured veneer or an artificially figured board, which is enable to easily and faithfully express figures in the form of those observed in nature in addition to normal grains of natural woods from the natural wood without figures with high productivity.
Another subject of the present invention is to provide an artificially figured veneer or an artificially figured board manufactured in the method of manufacturing therewith according to the method described.
The inventors carried out intensive investigation. As a result, it is found that all material veneers are uniformly embossed where multiple sheets of material veneers are simultaneously embossed by paying attention to the static bending strength (proportional limit) and specific gravity of the material veneers and determining the number of veneers to be embossed simultaneously according to theses value. The material veneers uniformly embossed produce no void between material veneers when laminated. And, simultaneous embossing of multiple sheets of material veneers leads to great improvement in the productivity of an artificially figured veneer compared to a prior method.
Therefore, the present invention relates to the method of manufacturing an artificially figured veneer or an artificially figured board, comprising the steps of
1) preparing at first a set of multiple sheets of material veneers by rotary cutting a log or repeatedly cutting a wood flitch from the certain kind of wood, wherein said multiple sheets of material veneers are of the same kind of wood with their grains sequential,
2) embossing concave-convex patterns simultaneously on said multiple sheets of material veneers whose number was determined according to the static bending strength (proportional limit) and specific gravity of the material veneers, with a pair of upper and lower press dies respectively having concave-convex patterns corresponding to a site of figure of a natural wood on both upper die and lower faces of die,
3) laminating the set of thus embossed multiple sheets of material veneers such that their grains again become sequential with the adhesive layer interposed between each material veneers, and pressing the laminate between the upper and the lower press dies, and
4) cutting the laminate obtained by the pressing in the direction crossing the plane of the lamination to manufacture an artificially figured veneer or an artificially figured board with desired thickness.
Relationship between static bending strength (proportional limit) and specific gravity of the material veneers and the number of veneers to be embossed simultaneously is concretely as follows;
In the case of specific gravityxe2x89xa60.49
If static bending strength (proportional limit)xe2x89xa6330 kg/cm2, then 3-6 sheets,
If static bending strength (proportional limit)xe2x89xa7330 kg/cm2, then 4-10 sheets.
In the case of 0.49 xe2x89xa6specific gravityxe2x89xa60.61
If static bending strength (proportional limit)xe2x89xa6400 kg/cm2, then 3-6 sheets,
If 400 kg/cm2xe2x89xa6static bending strength (proportional limit)xe2x89xa6540 kg/cm2, then 3-8 sheets,
If static bending strength (proportional limit)xe2x89xa7540 kg/cm2, then 4-8 sheets.
In the case of 0.61xe2x89xa6specific gravityxe2x89xa60.75
If static bending strength (proportional limit)xe2x89xa6540 kg/cm2, then 2-5 sheets,
If 540 kg/cm2xe2x89xa6static bending strength (proportional limit)xe2x89xa6710 kg/cm2, then 3-6 sheets,
If static bending strength (proportional limit)xe2x89xa7710 kg/cm2, then 3-8 sheets.
In the case of specific gravityxe2x89xa70.75
If static bending strength (proportional limit)xe2x89xa6820 kg/cm2, then 2-3 sheets,
If static bending strength (proportional limit)xe2x89xa7820 kg/cm2, then 2-6 sheets.
Thus, the present invention also relates to
the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, 3-6 sheets of the material veneers are embossed simultaneously when static bending strength (proportional limit) of said material veneers is below 330 kg/cm2, and 4-10 when it is above 330 kg/cm21 in case their specific gravity are below 0.49,
the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, 3-6 sheets of the material veneers are embossed simultaneously when static bending strength (proportional limit) of said material veneers is below 400 kg/cm2, 3-8 when it is above 400 kg/cm2 and below 540 kg/cm2, and 4-8 when it is above 540 kg/cm2, in case their specific gravity are above 0.49 and below 0.61,
the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, 2-5 sheets of the material veneers are embossed simultaneously when static bending strength (proportional limit) of said material veneers is below 540 kg/cm2, 3-6 when it is above 540 kg/cm2 and below 710 kg/cm2, and 3-8 when it is above 710 kg/cm2, in case their specific gravity are above 0.61 and below 0.75, and
the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, 2-3 sheets of the material veneers are embossed simultaneously when static bending strength (proportional limit) of said material veneers is below 820 kg/cm2, and 2-6 when it is above 820 kg/cm2, in case their specific gravity are above 0.75.
In the method for manufacturing, multiple sheets of material veneers is embossed with a pair of upper and lower press dies. At the time of embossing, pressure may be applied at once or stepwise up to predetermined level.
Therefore, the present invention relates to the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, the pressure is increased continuously up to predetermined level to emboss the material veneers, and the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, the pressure is increased stepwise up to predetermined level to emboss the material veneers.
At the time of embossing the material veneers, there is a case in which concave-convex pattern of press dies is transformed well to the surface of said material veneer by embossing with a cushioning material interposed between said material veneers and said press die.
Thus, the present invention further relates to the method of manufacturing an artificially figured veneer or an artificially figured board described above, wherein, in step 2, the material veneers are embossed with cushioning material interposed between said material veneers and said press die.
The method of manufacturing described above uses a set of multiple sheets of material veneers obtained from wood flitch of the same kind of wood as the raw material, but it is also expected that, when a set of multiple sheets of material veneers obtained from wood flitch with similar wood texture of specific family or specific species in place of such wood flitch is used as row material, the same effect can be achieved as the method of manufacturing described above.
Namely, above mentioned method of manufacturing can be applied to not only the case using material veneers of the same kind of wood but also the case using material veneers of specific family or specific species.
Therefore, the present invention also relates to the method of manufacturing an artificially figured veneer or an artificially figured board, comprising the steps of
1) preparing a set of multiple sheets of material veneers by rotary cutting a log or repeatedly cutting a wood flitch of wood of certain family or certain species, wherein said multiple sheets of material veneers have similar textures with their grains substantially sequential,
2) embossing concave-convex patterns simultaneously on said multiple sheets of material veneers whose number was determined according to the static bending strength (proportional limit) and specific gravity of the material veneers, with a pair of upper and lower press dies respectively having concave-convex patterns corresponding to a site of figure of a natural wood on both upper and lower faces of die,
3) laminating the set of thus embossed multiple sheets of material veneers such that their grains again become substantially sequential with adhesive layer interposed between each material veneers, and pressing the laminate between the upper and the lower press dies, and
4) cutting the laminate obtained by the pressing in the direction crossing the plane of the lamination to manufacture an artificially figured veneer or an artificially figured board with desired thickness.
Further, the present invention addresses the subject of an artificially figured veneer or an artificially figured board manufactured by the method according to any one of methods described above.